U.S. patent application Ser. No. 238,492 filed Feb. 26, 1981 and assigned to the assignee of the present invention, discloses the concept of varying the cross-sectional area of the spiroid swirl generating portion of a swirl generating engine cylinder inlet port in order to vary the amount of in-cylinder swirl obtained at differing engine speeds and cylinder air flow rates. This concept is exemplified by a variable area port arrangement which utilizes a flexible inner side wall that is movable to adjust the effective port area in a desired manner.